👤 María Medrano

Using longitudinal data from multiple cohorts, we evaluated plasma P-tau217 as a predictor of when cognitive impairment occurs in AD. P-tau217 concentrations were analyzed as continuous and binary variables using cohort-specific biomarker positivity thresholds. Association of plasma P-tau217 with prevalent and incident cognitive impairment were assessed using logistic regression and Cox models, stratified by Elevated P-tau217 levels were significantly associated with the onset of cognitive impairment. Among Plasma P-tau217 levels and the presence Show less

Epigenetic clocks associate with neuropathology and Alzheimer's disease (AD) clinical risk, but findings are mixed regarding whether clocks associate with blood-based biomarkers and in non-European populations. We calculated biological age and age acceleration from blood methylation data in 704 older Hispanic adults and tested associations with clinical diagnosis and antemortem biomarker levels. Age acceleration was significantly associated with sex, clinical diagnosis, and levels of eight plasma biomarkers, including P-tau217 levels. Additionally, biomarker associations trended more significantly among APOE-ε4 non-carriers. We also identified that methylation levels in CD4 and CD8 T-cell types are associated with age acceleration. We demonstrated that biological age acceleration, measured in blood, in a Hispanic cohort enriched for preclinical individuals, can stratify clinical AD risk and is associated with plasma AD biomarker levels. Blood-based aging clocks associate with Alzheimer's disease plasma biomarker levels. Biological aging appears relevant to pathological aging in apolipoprotein E (APOE) -ε4 non-carriers. Immune T-cell composition relates to biological aging. Show less

Circulating metabolites can identify biochemical risk factors related to Alzheimer's disease (AD). We measured plasma metabolites in 1,068 participants of Caribbean Hispanic ancestry (250 patients with AD and 818 healthy controls) across 2 cohorts and analyzed their relationship with clinical AD, biomarker-supported AD and plasma biomarkers (P-tau181, P-tau217, P-tau231 and Aβ42:Aβ40). Amino acid metabolism pathways were enriched among metabolites associated with P-tau biomarkers, whereas sialic acid and N-glycan pathways were associated with Aβ42:Aβ40. Through several dimensionality reduction approaches, we identified an APOE-ε4 dependent relationship between lysophosphatidylcholines (lysoPCs) carrying polyunsaturated fatty acids and biomarker-supported AD and P-tau biomarkers. In an independent dataset of 110 postmortem brain tissues from non-Hispanic white participants, lysoPCs in the brain were also associated with AD neuropathological features. Our results show that biomarker-based diagnostic criteria identified an APOE-ε4 dependent association with lysoPCs, which play a critical role in the transport of neuroprotective polyunsaturated fatty acids into the brain, and AD. Show less

Core 1 biomarkers, such as amyloid positron emission tomography, capture the earliest biological changes leading to Alzheimer's disease (AD). While APOE is a major genetic factor, the contribution of other variants to Core 1 biomarkers remains unclear. The goal of this study was to determine whether genetic regulators of Core 1 biomarker levels predicted AD pathology better than genetic regulators of clinical AD. Among 955 non-Hispanic White individuals, polygenic scores (PGSs) were built using genome-wide association studies (GWASs) of amyloid PET, plasma tau phosphorylated at threonine 181 (p-tau181), cerebrospinal fluid (CSF) p-tau181, and clinical AD. Hispanic-specific PGSs were constructed in 515 individuals using plasma p-tau181 and clinical AD GWASs. Baseline and longitudinal associations with plasma biomarkers and cognition were assessed, and replication was conducted in separate cohorts. The Core 1 biomarker PGSs predicted AD pathology and associated cognitive performance better than the AD PGSs in both populations. The Core 1 PGSs show improved predictive value for AD-related plasma biomarkers and early cognitive changes. APOE ε4 explained more variance in plasma p-tau217 than in plasma p-tau181. PGSs based on Core 1 biomarkers outperformed AD PGSs in predicting plasma biomarkers and cognitive decline among asymptomatic individuals in non-Hispanic White and Hispanic individuals. However, the improvement in predictive power was modest and may vary by age. While the variance in p-tau181 and p-tau217 explained by individual Core 1 PGSs remains limited, the distinct genetic signals captured by the best-performing PGSs across different Core 1 biomarkers may provide an opportunity for developing an integrative Core 1 PGS that more effectively predicts plasma p-tau181 and p-tau217 levels than AD-based PGS. Show less

One of the challenges in hypertrophic cardiomyopathy (HCM) is to determine the pathogenicity of genetic variants and to establish genotype/phenotype correlations. This study aimed to: (1) demonstrate that We reviewed genetic tests performed in HCM probands at our institution. We carried out transcript analyses to demonstrate the splicing effect, and haplotype analyses to support the founder effect of Show less

Less than 10% of early-onset Alzheimer's disease (EOAD) is explained by known mutations. We conducted genetic linkage analysis of 68 well-phenotyped Caribbean Hispanic families without clear inheritance patterns or mutations in We identified 16 (logarithm of odds > 3.6) linked regions, including eight novel loci for EOAD (2p15, 5q14.1, 11p15.1, 13q21.22, 13q33.1, 16p12.1, 20p12.1, and 20q11.21) and eight regions previously associated with late-onset Alzheimer's disease. The strongest signal was observed at 16p12.1 (25 cM, 33 Mb; heterogeneity logarithm of odds = 5.3), ∼3 Mb upstream of the ceroid lipofuscinosis 3 ( This study supports the notion that the genetic architectures of unexplained EOAD and late-onset AD overlap partially, but not fully. Show less

In a whole-exome sequencing study of multiplex Alzheimer's disease (AD) families, we investigated three neuronal ceroid lipofuscinosis genes that have been linked to retromer, an intracellular trafficking pathway associated with AD: ceroid lipofuscinosis 3 (CLN3), ceroid lipofuscinosis 5 (CLN5), and cathepsin D (CTSD). We identified a missense variant in CLN5 c.A959G (p.Asn320Ser) that segregated with AD. We find that this variant causes glycosylation defects in the expressed protein, which causes it to be retained in the endoplasmic reticulum with reduced delivery to the endolysosomal compartment, CLN5's normal cellular location. The AD-associated CLN5 variant is shown here to reduce the normal processing of cathepsin D and to decrease levels of full-length amyloid precursor protein (APP), suggestive of a defect in retromer-dependent trafficking. Show less

To describe the clinical, biochemical, and genetic features of patients with congenital disorders of glycosylation (CDG) identified in Spain during the last 20 years. Patients were selected among those presenting with multisystem disease of unknown etiology. The isoforms of transferrin and of ApoC3 and dolichols were analyzed in serum; phosphomannomutase and mannosephosphate isomerase activities were measured in fibroblasts. Conventional or massive parallel sequencing (customized panel or Illumina Clinical-Exome Sequencing TruSight One Gene Panel) was used to identify genes and mutations. Ninety-seven patients were diagnosed with 18 different CDG. Eighty-nine patients had a type 1 transferrin profile; 8 patients had a type 2 transferrin profile, with 6 of them showing an alteration in the ApoC3 isoform profile. A total of 75% of the patients had PMM2-CDG presenting with a heterogeneous mutational spectrum. The remaining patients showed mutations in any of the following genes: MPI, PGM1, GFPT1, SRD5A3, DOLK, DPGAT1, ALG1, ALG6, RFT1, SSR4, B4GALT1, DPM1, COG6, COG7, COG8, ATP6V0A2, and CCDC115. Based on literature and on this population-based study of CDG, a comprehensive scheme including reported clinical signs of CDG is offered, which will hopefully reduce the timeframe from clinical suspicion to genetic confirmation. The different defects of CDG identified in Spain have contributed to expand the knowledge of CDG worldwide. A predominance of PMM2 deficiency was detected, with 5 novel PMM2 mutations being described. Show less

Fertility traits, such as heifer pregnancy, are economically important in cattle production systems, and are therefore, used in genetic selection programs. The aim of this study was to identify single nucleotide polymorphisms (SNPs) using RNA-sequencing (RNA-Seq) data from ovary, uterus, endometrium, pituitary gland, hypothalamus, liver, longissimus dorsi muscle, and adipose tissue in 62 candidate genes associated with heifer puberty in cattle. RNA-Seq reads were assembled to the bovine reference genome (UMD 3.1.1) and analyzed in five cattle breeds; Brangus, Brahman, Nellore, Angus, and Holstein. Two approaches used the Brangus data for SNP discovery 1) pooling all samples, and 2) within each individual sample. These approaches revealed 1157 SNPs. These were compared with those identified in the pooled samples of the other breeds. Overall, 172 SNPs within 13 genes (CPNE5, FAM19A4, FOXN4, KLF1, LOC777593, MGC157266, NEBL, NRXN3, PEPT-1, PPP3CA, SCG5, TSG101, and TSHR) were concordant in the five breeds. Using Ensembl's Variant Effector Predictor, we determined that 12% of SNPs were in exons (71% synonymous, 29% nonsynonymous), 1% were in untranslated regions (UTRs), 86% were in introns, and 1% were in intergenic regions. Since these SNPs were discovered in RNA, the variants were predicted to be within exons or UTRs. Overall, 160 novel transcripts in 42 candidate genes and five novel genes overlapping five candidate genes were observed. In conclusion, 1157 SNPs were identified in 62 candidate genes associated with puberty in Brangus cattle, of which, 172 were concordant in the five cattle breeds. Novel transcripts and genes were also identified. Show less

Glucocorticoids are commonly used as adjuvant treatment for side-effects and have anti-proliferative activity in several tumors but, on the other hand, their proliferative effect has been reported in several studies, some of them involving the spread of cancer. We shall attempt to reconcile these incongruities from the genomic and tissue-physiology perspectives with our findings. An accurate phenotype analysis of microarray data can help to solve multiple paradoxes derived from tumor-progression models. We have developed a new strategy to facilitate the study of interdependences among the phenotypes defined by the sample clusters obtained by common clustering methods (HC, SOTA, SOM, PAM). These interdependences are obtained by the detection of non-linear expression-relationships where each fluctuation in the relationship implies a phenotype change and each relationship typology implies a specific phenotype interdependence. As a result, multiple phenotypic changes are identified together with the genes involved in the phenotype transitions. In this way, we study the phenotypic changes from microarray data that describe common phenotypes in cancer from different tissues, and we cross our results with biomedical databases to relate the glucocorticoid activity to the phenotypic changes. 11,244 significant non-linear expression relationships, classified into 11 different typologies, have been detected from the data matrix analyzed. From them, 415 non-linear expression relationships were related to glucocorticoid activity. Studying them, we have found the possible reason for opposite effects of some stressor agents like dexamethasone on tumor progression and it has been confirmed by literature. This hidden reason has resulted in being linked with the type of tumor progression of the tissues. In the first type of tumor progression found, new cells can be stressed during proliferation and stressor agents increase tumor proliferation. In the second type, cell stress and tumor proliferation are antagonists so, therefore, stressor agents stop tumor proliferation in order to stress the cells. The non-linear expression relationships among DUSP6, FERMT2, FKBP5, EGFR, NEDD4L and CITED2 genes are used to synthesize these findings. Show less

In a marker-trait association study we estimated the statistical significance of 65 single nucleotide polymorphisms (SNP) in 23 candidate genes on HDL levels of two independent Caucasian populations. Each population consisted of men and women and their HDL levels were adjusted for gender and body weight. We used a linear regression model. Selected genes corresponded to folate metabolism, vitamins B-12, A, and E, and cholesterol pathways or lipid metabolism. Extracted DNA from both the Sacramento and Beltsville populations was analyzed using an allele discrimination assay with a MALDI-TOF mass spectrometry platform. The adjusted phenotype, y, was HDL levels adjusted for gender and body weight only statistical analyses were performed using the genotype association and regression modules from the SNP Variation Suite v7. Statistically significant SNP (where P values were adjusted for false discovery rate) included: CETP (rs7499892 and rs5882); SLC46A1 (rs37514694; rs739439); SLC19A1 (rs3788199); CD36 (rs3211956); BCMO1 (rs6564851), APOA5 (rs662799), and ABCA1 (rs4149267). Many prior association trends of the SNP with HDL were replicated in our cross-validation study. Significantly, the association of SNP in folate transporters (SLC46A1 rs37514694 and rs739439; SLC19A1 rs3788199) with HDL was identified in our study. Given recent literature on the role of niacin in the biogenesis of HDL, focus on status and metabolism of B-vitamins and metabolites of eccentric cleavage of β-carotene with lipid metabolism is exciting for future study. Show less

The mechanisms by which ethanol and inhaled anesthetics influence the nervous system are poorly understood. Here we describe the positional cloning and characterization of a new mouse mutation isolated in an N-ethyl-N-nitrosourea (ENU) forward mutagenesis screen for animals with enhanced locomotor activity. This allele, Lightweight (Lwt), disrupts the homolog of the Caenorhabditis elegans (C. elegans) unc-79 gene. While Lwt/Lwt homozygotes are perinatal lethal, Lightweight heterozygotes are dramatically hypersensitive to acute ethanol exposure. Experiments in C. elegans demonstrate a conserved hypersensitivity to ethanol in unc-79 mutants and extend this observation to the related unc-80 mutant and nca-1;nca-2 double mutants. Lightweight heterozygotes also exhibit an altered response to the anesthetic isoflurane, reminiscent of unc-79 invertebrate mutant phenotypes. Consistent with our initial mapping results, Lightweight heterozygotes are mildly hyperactive when exposed to a novel environment and are smaller than wild-type animals. In addition, Lightweight heterozygotes exhibit increased food consumption yet have a leaner body composition. Interestingly, Lightweight heterozygotes voluntarily consume more ethanol than wild-type littermates. The acute hypersensitivity to and increased voluntary consumption of ethanol observed in Lightweight heterozygous mice in combination with the observed hypersensitivity to ethanol in C. elegans unc-79, unc-80, and nca-1;nca-2 double mutants suggests a novel conserved pathway that might influence alcohol-related behaviors in humans. Show less